THE guinea pig, a favorite childhood pet, can experience some very grown-up medical problems. Take the case of Kasha, a pet guinea pig whose owner, Lila Levey of Staten Island, noticed the animal had an abnormally distended abdomen. Levey took Kasha to a vet. The prognosis: “Nothing could be done.”

So she did nothing, waiting almost a year before getting a second opinion. Guinea pigs are classified as “exotic” animals, and not every vet is trained to treat them, but unqualified vets don’t always admit this. The second vet took X-rays then referred the tiny, two-pound patient to the Upper West Side’s Center for Avian and Exotic Medicine.

“We knew instantly what the problem was,” says nurse Lorelei Tibbetts, hospital manager at this specialty hospital dedicated solely to guinea pigs, reptiles and other exotic pets. “If they’re not spayed, female guinea pigs often develop ovarian cysts,” Tibbetts explains. “Kasha’s cysts had grown so huge, they were in danger of bursting, which would have caused her death. So we performed surgery immediately.”

Most people don’t think of small pets as candidates for major surgery. But, Tibbetts says, “They need the same care as dogs and cats.”

That goes double for that other childhood pet, the hamster. While a guinea pig’s average life span is six years, “By the time you have a 1-year-old hamster, you’re talking about an older animal,” Tibbetts says. “We recommend that hamsters be checked every six months.”

The center promotes adopting rescued exotic pets rather than buying from pet stores. To inquire about guinea pig rescue, call the hospital at (212) 501-8750 or visit the Web site, avianandexoticvets.com